Topical corticosteroids, as a class, demonstrate anti-inflammatory, anti-pruitic and vasoconstrictive actions. They are generally used to relieve the redness, swelling, itching and discomfort of psoriasis, atopic dermatitis and other pathologies of the skin. While the mechanisms of the anti-inflammatory effects are unclear, there appears to be a correlation between the therapeutic effects of these compounds and their vasoconstrictive potencies. Vasoconstrictor assays have been used to compare and predict the relative therapeutic potencies of the drugs in this class (Goodman and Gilman's, “The Pharmacological Basis of Therapeutics”, Chapter 25, Tenth Edition).
Commercially, topical steroid products are available as creams, lotions and ointments. U.S. Pat. No. 3,892,856 describes the use of corticosteroids dissolved in polyethylene glycol and emulsified into an oleaginous bases. However, because of the undesirably low solubility of corticosteroids in such vehicles, higher levels of steroids are necessary in these topical products and therefore the costs have been higher and also their cosmetic elegance has been adversely affected.
Mometasone Furoate is a steroid having the chemical name, 9(alpha), 21-Dichloro-11(beta), 17-dihydroxy-16(alpha)-methylpregna-1,4-diene-3,20 dione 17-(2-furoate), the empirical formula C27H30Cl2O6, and a molecular weight of 521.4. Mometasone furoate is a fine white powder that is insoluble in water, slightly soluble in octanol, and moderately soluble in ethyl alcohol.
The exceptionally poor solubility of mometasone furoate has delayed the development of efficacious, economic and cosmetically elegant topical formulation. U.S. Pat. No. 4,808,610 describes the poor solubility and efficacy of oleaginous topical creams that have mometasone fuorate dissolved into propylene glycol. Additionally, the patent makes reference to a skin irritating effect of certain mometasone fuorate/propylene glycol formulations.
Surprisingly, we have been able to develop a mometasone fuorate cream that is topically effective and non-irritating to the skin. The cream is stable, has an effective biological activity and was found to be non-irritating to the skin when applied. The cream is an oleaginous, occlusive cream with propylene glycol.